A conventional rugged amphibious robotic ball 10 is shown in FIG. 1 which can carry a range of payloads. The ball 10 shown in FIG. 1 includes a shell 20 and operates by actuating a pendulum 70 about two independent axes. Movement of the pendulum 70 about the axis 40 propels the ball 10 to roll forward by moving the center of mass of the ball 10 in front of a contact patch with the ground. All or part of the hanging mass can rotate about the main axle 40, and all or part may rotate about an orthogonal axle 100. These two independent degrees of freedom control the forward motion and the steering angle of the ball, respectively. As the center of mass of the system shifts relative to the contact patch, the ball 10 rolls to compensate forming a rolling motion or performing a steering movement. This system requires a complicated system 120 for propulsion and steering which includes, inter alia, a primary motor 50, a secondary motor 90 and a transmission arrangement 110. In particular, with the conventional design, the two degrees of freedom are implemented in orthogonal axes making the packaging of such a system difficult and requires a large portion of the volume of the sphere to be hollow space that allows for complete movement of the pendulum in both axes.
Accordingly, there is a need for a less complicated system for propulsion and steering.